What’s wrong with constexpr?
Back when I made this, GCC/clang were crashing left and right while compiling my project because of constexpr and auto usage with nested lambdas. It got worse with every template being evaluated until the compiler and my IDE started crashing.
I was making a react-like UI component library with all the new bells and whistles of modern C++. It was fun at first then the issues cropped up and it kinda killed my passion for the language and drove me away entirely.
Not sure about its state nowadays though.
I see. I think auto gets overused a lot by people just being lazy about writing out the full type, but constexpr is good practice in my opinion. Never had a compiler issue with them, but then I don’t think I’ve ever used a nested lambda either.
The problem is that lambdas with a capture
aren’t strongly typedare uniquely typed, so you have to use decltype/auto. And if you pass such a lambda to a function you’ll have to use auto as well.If you write a lambda with a capture that calls itself recursively you’ll have to pass it to itself as an auto argument as part of the call signature.
I think this article explains it better: https://artificial-mind.net/blog/2020/09/12/recursive-lambdas
Edit: fixed wrong terminology
This is an entirely new way to misuse “strongly typed” that I was not aware of before. Amazing.
Thank you!
You’re welcome. Just don’t blame me when your brain starts cursing in foreign languages you don’t even know. ;)
I really like C++ (I know, shoot me), and I think
auto
should be avoided at (almost) all costs.One of the things I love about a language like C++ is that I can take one glance at the code and immediately know what types I’m working with.
auto
takes that away while adding almost no benefit outside of a little convenience while writing.If I’m working with some very big template type that I don’t want to write out, 99/100 times I’ll just have a
using
somewhere to make it more concise. Hell, I’ll haveusing vectord = std::vector<double>
if I’m using a lot of them, because I think it makes the code more readable. Just don’t throwauto
at me.Of course, the worst thing ever (which I’ve seen far too often) is the use of
auto
in examples in documentation. Fucking hell! I’m reading the docs because I don’t know the library well! When you first bother to write examples, at least let me know the return type without needing to dig through your source code!Thanks, that was a good read :)
However, my impression is that he’s largely using the existence of templates and polymorphism as arguments that “we don’t really care about type”. I disagree: A template is essentially a generic type description that says something about what types are acceptable. When working with something polymorphic, I’ll prefer
ParentClass&
, to indicate what kind of interface I’m working with.Sure, it can be very useful to hide exact type information in order to generalise the code, but I think that’s a weak argument for hiding all type information by default, which is what
auto
does.
Integrated divinity environment